雅思听力

🎧 Listening Transcript

Good morning, everyone. Today we're going to look at the history of the bicycle. Now, you might think the bicycle was invented in the 19th century, and you'd be right. But the first two-wheeled vehicle, called a 'velocipede', appeared in 1817. It had no pedals; you pushed it along with your feet. Later, in the 1860s, pedals were added to the front wheel. However, this design was unstable because the front wheel was small. It wasn't until the 1880s that the 'safety bicycle' with a chain drive and two equal-sized wheels became popular. So, the key improvement in the 1880s was...